It is equipped with the RE-115 K mic input transformer and the proprietary API output transformer found in the 512c single mic pre and throughout the API product line. The unit has an internal 48-volt phantom power supply, which is switchable for each channel, as well as -20dB pad switches that affect both the mic and Hi-Z instrument inputs, both located on the front panel. Another feature of the 3124+ is that it can provide up to 65dB of gain to an output clip level of +28dBu. Additionally, the Hi-Z front panel inputs feed directly to the op amps, which allow a low level input such as a guitar or bass to be amplified without a matching transformer or direct box. These Hi-Z inputs can take input levels as high as +20dBu, making them perfect for keyboards and other high level devices.The mic preamp outputs are on rear panel male XLR connectors. The item "API 3124+ 4-channel Mic/Instrument Preamp" is in sale since Wednesday, April 27, 2016. This item is in the category "Musical Instruments & Gear\Pro Audio Equipment\Preamps & Channel Strips". The seller is "studio_drums" and is located in Newark, Delaware. This item can be shipped to United States.